1. Field of the Invention
The present invention relates to an electronic element wafer module in which an optical filter layer is provided on a cover glass which protects a plurality of electronic elements; a method for manufacturing the electronic element wafer module; an electronic element module formed by cutting the electronic element wafer module into pieces; an electronic element module in which an optical element is further attached thereon; and an electronic information device, such as a digital camera (e.g., a digital video camera and a digital still camera), an image input camera, a scanner, a facsimile machine, and a camera-equipped cell phone device, having any of the electronic element modules as an image input device used in an image capturing section thereof.
2. Description of the Related Art
Digital cameras and video cameras using a sensor module, functioning as a electronic element module, as an image input device in an image capturing section thereof have conventionally come into wide use.
Currently, commonly used sensor modules are formed, for example, of a solid-state image capturing element chip in which the solid-state image capturing element is provided on a silicon semiconductor substrate; a ceramic package for housing the solid-state image capturing element chip; and a transparent cover glass for encapsulating the package. The solid-state image capturing element chip housed in the package is connected to circuits on a printed circuit board by electrically connecting an electrode pad provided on the solid-state image capturing element chip with a connection terminal of the package by wire bonding, and by installing an external connection terminal of the package on the printed circuit board.
It is also practiced to install a solid-state image capturing element as an electronic element into a small electronic information device, such as a cell phone device and an electronic notebook to add a photographing function. In order to facilitate the installation of the photographing function into the small electronic information device, an optical unit, which includes a solid-state image capturing element and an image-capturing optical system installed therein, and a printed circuit board provided with a control circuit thereon are assembled in advance and they are unitized, so that a camera module having such a configuration is provided.
Reference 1 discloses a conventional camera module in which an infrared ray cut filter and an optical low pass filter are installed in order to improve the picture quality. FIG. 10 illustrates such a conventional camera module.
FIG. 10 is an essential part longitudinal cross sectional view schematically illustrating one example of the conventional camera module disclosed in Reference 1.
In FIG. 10, a conventional solid-state image capturing apparatus 100 includes: a solid-state image capturing element chip 103 in which a plurality of solid-state image capturing elements 102 are provided on a semiconductor substrate 101 (semiconductor wafer); a frame section 104 for enclosing an area for forming the solid-state image capturing elements 102, the frame section 104 being provided on the solid-state image capturing element 102 side of the solid-state image capturing element chip 103; a cover glass 105 provided on the frame section 104 for functioning as a transparent support substrate that hermetically seals each of the solid-state image capturing elements 102; an infrared ray cut filter substrate 106 attached on top of the cover glass 105 to improve the picture quality; and an optical low pass filter substrate 107 attached on the infrared ray cut filter substrate 106.
The infrared ray cut filter substrate 106 and the optical low pass filter substrate 107 are positioned in such a manner to cover the solid-state image capturing elements 102. A common infrared ray cut filter includes a laminated structure of a titanium oxide film or tantalum oxide film and a silicon oxide film.
On the other hand, Reference 2 discloses a niobium oxide film (Nb2O5) as a material for an infrared ray cut filter.
Reference 1: Japanese Laid-Open Publication No. 2006-32886
Reference 2: Japanese Laid-Open Publication No. 2006-351615